<script setup lang="ts">
import classifyData from "@/common/classify.data.js";
import {getCurrentInstance, nextTick, onMounted} from 'vue';

const instance = getCurrentInstance();
import {ref} from "vue";
import {reqCategory} from "@/api/category";
import {onLoad} from "@dcloudio/uni-app";

const tabData = ref([])

onLoad(async (options) => {
  //获取分类
  await reqCategory().then((res) => {
    if (res.code == 200) {
      tabData.value.push(...res.data)
    }
  })
})

let scrollTop = ref(0);//tab标题的滚动条位置
let oldScrollTop = ref(0);
let itemId = ref('');
let current = ref(0);
let menuHeight = ref(0);
let menuItemHeight = ref(0);
let menuItemPos = ref([]);
let arr = ref([]);
let scrollRightTop = ref(0);
let timer: any = null;
// 获取一个目标元素的高度
const getElRect = (elClass, dataVal) => {
  new Promise((resolve, reject) => {
    const query = uni.createSelectorQuery().in(instance);
    query.select('.' + elClass).fields({size: true}, res => {
      // 如果节点尚未生成，res值为null，循环调用执行
      if (!res) {
        setTimeout(() => {
          getElRect(elClass);
        }, 10);
        return;
      }
      dataVal.value = res.height;
      resolve();
    }).exec();
  })
}
// 点击左边的栏目切换
const swichMenu = async (index) => {
  if (arr.value.length == 0) {
    await getMenuItemTop();
  }
  if (index == current.value) return;
  scrollRightTop.value = oldScrollTop.value;
  await nextTick(() => {
    scrollRightTop.value = arr.value[index];
    current.value = index;
    leftMenuStatus(index);
  })
}
// 设置左边菜单的滚动状态
const leftMenuStatus = async (index) => {
  current.value = index;
  // 如果为0，意味着尚未初始化
  if (menuHeight.value == 0 || menuItemHeight.value == 0) {
    await getElRect('menu-scroll-view', menuHeight);
    await getElRect('u-tab-item', menuItemHeight);
  }
  // 将菜单活动item垂直居中
  scrollTop.value = index * menuItemHeight.value + menuItemHeight.value / 2 - menuHeight.value / 2;
}
// 获取右边菜单每个item到顶部的距离
const getMenuItemTop = () => {
  new Promise(resolve => {
    let selectorQuery = uni.createSelectorQuery();
    selectorQuery.selectAll('.class-item').boundingClientRect((rects) => {
      // 如果节点尚未生成，rects值为[](因为用selectAll，所以返回的是数组)，循环调用执行
      if (!rects.length) {
        setTimeout(() => {
          getMenuItemTop();
        }, 10);
        return;
      }
      rects.forEach((rect) => {
        // 这里减去rects[0].top，是因为第一项顶部可能不是贴到导航栏(比如有个搜索框的情况)
        arr.value.push(rect.top - rects[0].top);
        resolve();
      })
    }).exec()
  })
}
// 右边菜单滚动
const rightScroll = async (e) => {
  oldScrollTop.value = e.detail.scrollTop;
  if (arr.value.length == 0) {
    await getMenuItemTop();
  }
  if (timer) return;
  const itemHeight = ref(0)
  if (!menuHeight.value) {
    await getElRect('class-item', itemHeight);
  }
  setTimeout(() => { // 节流
    timer = null;
    // scrollHeight为右边菜单垂直中点位置
    let scrollHeight = (e.detail.scrollTop + itemHeight.value / 2) + 110;
    for (let i = 0; i < arr.value.length; i++) {
      let height1 = arr.value[i];
      let height2 = arr.value[i + 1];
      // 如果不存在height2，意味着数据循环已经到了最后一个，设置左边菜单为最后一项即可
      if (!height2 || scrollHeight >= height1 && scrollHeight < height2) {
        leftMenuStatus(i);
        return;
      }
    }
  }, 10)
}

const toList = (item: any) => {
  uni.navigateTo({
    url: `/pages/category/categoryList/categoryList?id=${item.id}&title=${item.name}`
  })
}

</script>

<template>
  <view class="bar"></view>

  <view class="u-wrap">
    <view class="u-search-box">
      <view class="u-search-inner">
        <u-icon name="search" color="#909399" :size="28"></u-icon>
        <text class="u-search-text">搜索</text>
      </view>
    </view>
    <view class="u-menu-wrap">
      <scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop"
                   :scroll-into-view="itemId">
        <view v-for="(item,index) in tabData" :key="index" class="u-tab-item"
              :class="[current == index ? 'u-tab-item-active' : '']"
              @tap.stop="swichMenu(index)">
          <text class="u-line-1">{{ item.name }}</text>
        </view>
      </scroll-view>
      <scroll-view :scroll-top="scrollRightTop" scroll-y scroll-with-animation class="right-box" @scroll="rightScroll">
        <view class="page-view">
          <view class="class-item" :id="'item' + index" v-for="(item , index) in tabData" :key="index"
          >
            <view class="item-title">
              <text>{{ item.name }}</text>
            </view>
            <view class="item-container">
              <view class="thumb-box" v-for="(item1, index1) in item.categoryChild" :key="index1" @click="toList(item1)">
                <!--                <image class="item-menu-image" :src="item1.icon" mode=""></image>-->
                <up-avatar size="70" :src="'https://'+item1.icon"></up-avatar>
                <view class="item-menu-name">{{ item1.name }}</view>
              </view>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<style scoped lang="scss">
.u-wrap {
  height: calc(100vh);
  /* #ifdef H5 */
  height: calc(100vh - var(--window-top));
  /* #endif */
  display: flex;
  flex-direction: column;
}

.u-search-box {
  padding: 18rpx 30rpx;
}

.u-menu-wrap {
  flex: 1;
  display: flex;
  overflow: hidden;
}

.u-search-inner {
  background-color: rgb(234, 234, 234);
  border-radius: 100rpx;
  display: flex;
  align-items: center;
  padding: 10rpx 16rpx;
}

.u-search-text {
  font-size: 26rpx;
  color: $u-tips-color;
  margin-left: 10rpx;
}

.u-tab-view {
  width: 200rpx;
  height: 100%;
}

.u-tab-item {
  height: 110rpx;
  background: #f6f6f6;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26rpx;
  color: #444;
  font-weight: 400;
  line-height: 1;
}

.u-tab-item-active {
  position: relative;
  color: #000;
  font-size: 30rpx;
  font-weight: 600;
  background: #fff;
}

.u-tab-item-active::before {
  content: "";
  position: absolute;
  border-left: 4px solid $u-primary;
  height: 32rpx;
  left: 0;
  top: 39rpx;
}

.u-tab-view {
  height: 100%;
}

.right-box {
  background-color: rgb(250, 250, 250);
}

.page-view {
  padding: 16rpx;
}

.class-item {
  margin-bottom: 30rpx;
  background-color: #fff;
  padding: 16rpx;
  border-radius: 8rpx;
}

.class-item:last-child {
  min-height: 100vh;
}

.item-title {
  font-size: 26rpx;
  color: $u-main-color;
  font-weight: bold;
}

.item-menu-name {
  font-weight: normal;
  font-size: 24rpx;
  color: $u-main-color;
}

.item-container {
  display: flex;
  flex-wrap: wrap;
}

.thumb-box {
  width: 33.333333%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  margin-top: 20rpx;
}

.item-menu-image {
  width: 120rpx;
  height: 120rpx;
}
</style>
